Tissue resection procedures, such as colonoscopy and polypectomy, are carried out by inserting introduction sheaths, such as endoscopes or laparoscopes, into the body of a patient through incisions or natural anatomical openings (e.g., oral, vaginal, and/or anal cavities). Commonly, such devices employ snares, typically designed as loops, for performing tissue resection procedures. However, snares have a tendency to slip off targeted tissue, often requiring repeated efforts to capture the tissue before the resection procedures can be successfully performed. In addition, a typical snare has low stiffness and requires a shallow angle of approach. These properties may reduce operability of the snare during the resection procedure.
Various methods have been developed to improve the functioning of snares. For example, one common approach is to apply a downward force on the snare to improve traction between the snare and the unwanted tissue. This downward force is usually limited due to a lack of stiffness in the snare, which may cause the distal end of the snare to deflect away from the tissue. In order to control this deflection, the downward force may continue to be applied or it may be increased until the tissue is snared. Continued or increased applied force increases the risk of accidentally damaging surrounding tissues, as well as increases the time required to complete a procedure. Further, it may be sometimes difficult to apply the necessary downward forces due to geometric and physical limitations such as shallow angle of approach required by the snare.
Therefore, there exists a need in the art for an improved snare with better engagement capabilities, thereby allowing consistent capture, excision, and/or removal of unwanted tissue.